Two-phase high-frequency electric alternating-current generator



,Man 27 1923;?

M., c. A. LATOUR TWO-PHASE HIGH FREQUENCY ELECTRIC ALTE RNATING CURRENTGENERATOR Filed Jun e 25, 1920 Wlfiesges Mar. 27, 1923. V

UNITED STATES PATENT OFFICE.

MARIUS C. A. LATOUR, OI LONDON, ENGLAND.

To ail whom it may concern:

B e it known that I, MARIUQ. C. A. LA- TOUR, citizen of the Republic/ fFrance, residing in London, England, have invented 5 certain new anduseful Improvements in Two-Phase High-Frequency ElectricAlternating-Current Generators, of which the following is aspecification.

This invention relates to high frequency homopolar alternatorsgenerating two phase Applicatibx filed June 23,1920. Serial m5.391,1;00.

Figure 2 shows the moments when the flux 55 is a maximum and Figure 3the moment when it is' a minimum.

. Referring to Fig. 1, the exciting rotor 1 carries polar projectionsthe width of which in the air gap is for example, equal to that 60 ofthe empty spaces which represent the magnetic poles of opposite sign.The stator 2 carries slots .the width of which for example is equal tothat of the polar procurrents and. having stator slots "01asize---jections 0" empty spaces of the rotor d 65 relatively important.The frequencyof the current produced by this alternator 18 that usuallyused with wireless telephony and telegraphy. It is well known that.polyphase alternators possess. the advantage of having a power per unitvolume and an output higher than single phase alternators. It is more-20 over known that a wireless aerial can be fed by means of two phasecurrent as shown for The invention is described in the accom-I payingdrawings in which igure 1 shows the stator teeth (above) and the rotorteeth (below) and the arrangement in the stator slots of two coils eachbelonging to the winding of one of the two phases.

' F'gures 2 and 3 show the same parts in two different positions inorder to set forth the variation in the flux in one coil when the rotoris' displaced.

The whole of the machine including the exciting winding is not shown asit forms no part of the invention.

The present invention can be applied as has been already stated above toa homo-- polar alternator of any type whatever andcpnsists only of themodification effected in the teeth and the winding of this alternator 1in Gilldl to cause the generation of two phase hig frequency currents.It is suiiicient to state that the exciting flux, the path of which isshown.in Figs.

2 and 3, does not change direction, and that, during the rotation of therotor, it only undergoes periodic variations in intensity.

has teeth of halfthatparidth.

In the stator slots two distinctfwinelingsa. are alternately arranged inthe manner shown in Figure 1 in which 3 represents a coil belonging tothe first winding and 4 a coil belonging to the other winding. The twocoils are crossed as in the case of two phase windings.

It will be shown that under these conditions the ratio of the number ofteeth of 7 the stator to the number of teeth of the rotor is 4 to 3.

This ratio is speciallyadopted in this case in order to produce twophase high frequency current and cannot be compared with a ratio havingthe same figures which may have been already applied to a machinegenerating single phase high frequency current and wound necessarily inanother manner without crossed coils.

It will be easily seenby referring to Figures 1, 2 and 3 that, with thisparticular construction in the positions shown in Figures land 2 theflux is a maximumin the coil 3. WVhen' the tooth 10 of the rotor isdisplaced to the right a distance equal to its width. the flux will be aminimum in this coil and the electromotive force in 3 will haveundergone half acycle. On the other hand, in the coil 4, the flux is aminimum when the -rotor is displaced a distance equal to half the widthof a tooth relatively to the position' shown in Figure .l and maximumwhen it.is displaced a distance equal to one and a half times the widthof a tooth.

It will'thusbe seen that the fluxes in the two windings are out of phaseby an angle equal to It is the same for the current in of the latter bya distance equal to twice the width of a tooth corresponds to theproduction of one period of alternating current.

Although in the drawings, the slots shown I are of the open type theinvention is not.

restricted to this type of slots and could equally be applied tomachines'having close rotor it is necessary therefore, either to make ior half closed. slots. v v

I It must be noted that in a similar two 7 phase machine generatingcurrent of fre-' quencyj, the reaction flux produced by the excitingrotor as in 'the ordinary two phase machine but on the contrary rotatesat aspeed equal to 7 relatively to the exciting rotor.

Inorder to avoid excessive losses in this it in a laminated form or toadd to it a dampingsystein formed for example by a a squirrel cage inorder'to choke down the reaction flux. g n I declare that what I claimis A homo-polar high frequency alternator I wound for two, phasecurrentcomprising-a rotor having'a large number of magnetic poles, astator. having slots arranged opposite the poles of said rotor, 'thenumber of stator slots being to' the'number of rotor slots in" the ratioof 4 to 3, and a winding carried by said stator slots each coil of saidwinding encircling two teeth. and adjacent coilsmutuallyerossing oneanother. In witness whereofyI have hereunto signed my namethis 9th dayof June, 1920,- in the presence of two subscribing Witnesses.

MARIUS o. A. ToUR,

' Witnesses:

' JAMES} ELLIS, JOSEPH L. SHULIN.

